Manufacture of flour



p E. A. FISHER EI'AL I 1,727,429

MANUFACTURE 0 FLOUR Filed May 25, 1928 fmesf Ar1hur fisher Charles KOberT Jones miter An'rm rxsnnn the baking qualities Patented Se t, 10, 1929.

. UNITED STATES,

PATENT 'oFFIc nonnnr :roimaor s r. means, nnemiin. k a

MANUFACTURE" or rnogip Application filed Bay 25, 1928, Serial No. 280,579, and in Great Britain larch- 27 1928.

This inventibn relates to; the heat treatment of flour for the purpose of improving thereof, and has for its object to provide animproved process and means therefor, whereby the flour may e co' nomically be treated with expedition and certainty. a

It has previously been proposed to subject flour to heat treatment under non-oxidizing conditions, e. g. in the presence of steam or moist air or' in a substantially closed vessel, and it has also been proposedto heat dry or damp wheat out of contact with air currents but underconditions'which permit free escape of moisture evaporated therefrom.

I In our co-pendingBritish application No. 15,542/27 is'described a rocess for improving the baking quality oi flour, according to which thin layers of flour-are subjected to heat treatment ina current of air of such temperature and humidity, as will raise the flour to and maintain it at a temperature of within the approximate limits of 130 andl80 F.

without substantial loss of moisture. In the process accordin to the present invention, the flour in clou form is subjected to treatment by a current of air which is at such temperature and humidity as will raise the temperature of theflour to within the approximate limits of 130and 180 F. without substantial loss of moisture.

This me hod, which has the advantage of reducin t e time required for the treatment, besides eing automatic, and-continuous in action, will be described, by way of example, with reference to the accompanying drawing which is a diagrammatic sectional elevation of an apparatus which may be used.

As shown inthe drawing flour is passed from a conveyor (1 (of such a type thatit is capable of delivering a regular feed at a known rate) down a chute b on to a disc 0 which rotates rapidly below the lower-end 4 of the chute b in a chamber (1 so that the flour fied air enterin chamber 11 is driven upwards past the disc 0 is broken up and flung' centrifugally into a thin cloud. A stream of heated and humidiat the lower end' e of the at such avelocity as to carry the flour with it. The "air and flour pass from the chamber vthe finest flourparticles not.

insulated box or small bin (not shown) where it may remain for a short time' if desired. .4

The time re uired for maximum improvement is uite s ortand appears to depend on several ctors' which include moisture content of, and temperature reached by, the flour. In controlling the operation, it appears to be important that the humidity of the .air lea ving the cyclone, where-the flour has been deposited, should be highpreferably over 90% relative humiditya condition which can be assured by attention to such factors as rate of feed .of fiour,.temperature,

humidity and velocity of entering air. In

this way not only does little or no loss of moisture from the flour occur during treatment, but the extent of the improvement may be increased or the time in which it is effected shortened. a

vAs an'illustration, in the case of one low grade flour from the tailof the mill (representing about 15% of the total flour stream) the temperature of'the air leaving the cyclone was 145? F. and its relative humidity 90%. One passage'through the plant and 10 minutes lying-in 'the'bin produced substantial improvement in the quality of the flour.- The temperature reached by the flour was roughly 140 F. and its moisture content (14 to Li was substantially unchanged by the treatment.

After treatment the flour may be led away from the bin through a conveyor (a) into a second machine where the flour may be-cool'ed by blowing humidified air through it in the same manner, or (6) into a chamber where it may be both-cooled and moistened by spraying with cold air and finely atomized water as in the Humphries process; or (c) the flour may be cooled in any other convenient manner. I This treatment can be applied not only to finished flour but to those intermediate types of milling stock, such as semolina middlings and dunst, from which most'of the germ and bran have been removed, and to any or all of the various divides from which the final flour is made by mixing. This point is important as not all parts of the same flour stream may require treatment; and .by dividing the feed in an appropriate manner any divide or group of divides may be treated as desired.

The improvements in flour due to this treatment are I (1) An increase in dough stabilit (2) Increased water absorption by dough.

(3) Larger loaf.

(4) Better shaped loaf-other than tinned.

(5) Frequently a better loaf colour (crumb) this is not a bleaching action as the colour of the extracted oil does not appear to be effected.

These improvements are essentially those brought about by the addition of chemical improvers to flour. Not all flours however, can be improved either by chemical improvers or by heat treatment. \Veaker flours can, however, be made stronger by such treatment and to a marked extent.

An important advantage of the process is that it may be used for the purpose of sterilizing flour in the sense of destroying acarids or mites, (Aleurobi'us fam'me). The process may be carried out with this as the primary Hbject and/or with a view to improving the our.

Thus a sample of badly mite-infested flour, treated in the same manner as the low-grade flour in the illustration quoted above, was found to be free from living mites immediately after treatment and none were found to develop during subsequent storage, showing that the flour'had been sterilized efiiciently, i. e., that the eggs and larvae had been destroyed as well as the adult pests.

\Ve claim 1. A process for improving the baking quality of flour, wherein the flour in cloud form is subjected to treatment by a strong current of air which is at such temperature and humidity as will raise the temperature of the flour to within the approximate limits of and F. without substantial loss of moisture, substantially as set forth.

2. A process as claimed in claim 1 in which the relative humidity of the air current exceeds 90%.

ERNEST ARTHUR FISHER. CHARLES ROBERT JONES.

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